1. Field of the Invention
The present invention concerns a device for determining the position of at least one local coil arranged or to be arranged on a patient bed of a magnetic resonance device, and a magnetic resonance system with such a device. In addition, the invention concerns a method for position determination of at least one local coil arranged or to be arranged on a patient bed.
2. Description of the Prior Art
For various applications in the field of magnetic resonance, it is necessary to detect the position of different local coils directly arranged on a patient located on a patient bed, or directly arranged on the patient bed. Such local coils are provided in order to be able to generate exposures of higher quality of specific regions of a patient. For example, head coils, torso coils, back coils, leg coils and the like are known.
In order to be able to establish the position of these coils on the bed, it is known to produce a magnetic resonance measurement and to evaluate the acquired magnetic resonance data with regard to the coil position or orientation. However, this known procedure has disadvantages.
First, only the local coils that do not lie far from the isocenter of the magnetic resonance device are detected. The detected range is within about 25 cm around the isocenter, for instance. All local coils that lie outside of this search window are not detected or may be incorrectly detected. Magnetic resonance-specific artifacts are responsible for this, in particular the nonlinearity of the gradients outside of the field of view or disruptions by the patient himself. Even within the search window, the precision of the position detection is at best in the range of a few centimeters. Finally, the measurements are time-consuming since they require multiple seconds and scale with the number of the local coils to be detected. If it were desired to detect all local coils with this method, a patient would have to be measured from head to toe at multiple points, such that the time would extend into the range of minutes.